Boiler, particularly suitable for locomotives



May 25, 1954 v v P. CROSTI BOILER, PARTICULARLY SUITABLE FOR LOCOMOTIVES 5 Sheets-Sheet 1 Filed April 4, 1950 mvEHToR:

mm CR0! 6Y f 4"! I May 25, 1954 c os I 2,679,238

BOILER, PARTICULARLY SUITABLE FOR LOCOMOTIVES Filed April 4, 1950 5 Sheets-Sheet 2 INVEHTORZ P ERG C RUST,

P. CROSTI May 25, 1954 BOILER, PARTICULARLY SUITABLE FOR LOCOMOTIVES 3 Sheets-Sheet 5 Filed April 4, 1950 IHVEHToR:

PIERO Cmsw BY" Patented May 25, 1954 UNITED STATES PATENT OFFICE BOILER, PARTICULARLY SUITABLE FOR LOCOMOTIVES Piero Crosti, Milan, Italy Application April 4, 1950, Serial No. 153,864 Claims priority, application Italy June 9, 1949 Claims. 1

It is the object of the present invention ,to provide a boiler for the production of steam, particularly suitable for installation on locomotives, wherein heating and vaporizing are efiected in separate and successive steps.

To this end, besides the cylindrical boiler body containing a set of flues between the firebox and the smoke chamber, and below said body, there is arranged at least one further shell, which has an inlet orifice for feed water at one end,

' and is in communication with said cylindrical boiler body at the opposed end.

The lower shell contains another set of smoke tubes in communication, on one side, with the aforesaid smoke chamber and on the other side with the chimney.

Some forms of embodiment of the boiler are illustrated merely by way of example in the accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view of a boiler with a polyhedral chest furnace;

Fig. 2 is a fragmentary longitudinal sectional view of a boiler with a corrugated cylindrical flue;

Fig. 3 is a cross-sectional view on line LIL-III in Fig. 1;

Fig. 4 is a cross-sectional view on line IV-IV in Fig. l;

Figs. 5 and 6 are fragmentary longitudinal sectional views of details; and

Fig. '7 is a longitudinal sectional view of a modified embodiment.

The reference numeral l designates the cylindrical boiler body or shell, 2 the chest furnace (Fig. 1) and 3 the corrugated cylindrical flue (Fig. .2).

Two cylindrical preheater bodies 6 are located in the lower portion of the smoke chamber 4 and project through the wall 5 outwardly and under the boiler shell I.

These cylindrical bodies are arranged with their axes slightly inclined in relation to the axis of the boiler body I, as shown in the drawing, thus attaining a more compact design, greater facility in mounting, easier maintenance,'and better movement of the fluids therein which contributes to the good thermal eificiency of the entire assembly.

In each of these lower cylindrical preheater bodies 6 there is arranged a set of preheater tubes 1 secured to the tube plates 8 and 9 which are arranged at the ends of said cylindrical bodies. These plates, the edges of which are differently shaped and have different diameters, namely larger in the plate 9 than in the plate 8, are retained in the seats ii) and H by annular members l2 and I3. Screws it and I5, respectively, press the members l2 and it against the plate 8 and the flange it which is connected to the cylindrical body 6. With such an arrangement, it is made possible to extract the set of preheater tubes 1 from the cylindrical body, together with the tube plates 8 and 9, and then to proceed to remove the precipitated salts deposited by water during the heating stage without any difficulty. The cylindrical preheater bodies 6 are connected to the wall 5 bythe flange H and bolts 18,-and are suspended at the outwardly projecting end thereof from the body I of the boiler by supports It.

The supports l9 consist of resilient metal sheets and allow longitudinal expansion and contraction of the cylindrical preheater bodies, caused by difierent thermal expansion of the same with respect to the shell 'I.

The projecting end of thepreheater body 6 is secured to a smokebox 29, from which the chimneys 2! project upwardly on both sides of the cylindrical body I.

The gaseous products of combustion developing in the firebox 2 (Fig. 1) or flue 3 (Fig. 2) of the boiler 4, flow through the set of fines 22 and into the smoke chamber 4 and after flowing partly along over the outer wall of the lower cylindrical preheater bodies 6, they enter the nest of preheater tubes 1, then arrive at the smokebox Eli and eventually escape from the chimney 2|.

The smoke chamber 4 is closed by a door 23 the width of which permits performing of any operation of attending to the boiler, including extraction of the nests of preheater tubes 1.

Fig. 7 shows a modified embodiment of the invention by which a more rational and economic operation is attained. In the case that solid particles are mixed with the combustion gases, deposition of these solid particles in tubes '1 must be prevented. For this purpose a substantially horizontal partitioning means 24 extending above the cylindrical bodies 6 is provided and, conse quently, in order to retain solid ash particles on said partition 2d, the door 25 is shaped in such a manner as to guide the gases around surface E l.

A conduit 25 of sufiicient width is provided in the structure of the door for conveying the combustion gases from the upper portion of the smoke chamber 4 to the lower portion opposite the tube platese of the cylindrical bodies 5. vertical wall portion 25 is provided to retain ashes on the zone 21, indicated by dotted lines.

3 If the door is opened, wall portion 26 is withdrawn automatically so as to allow cleaning.

By this arrangement, the preheater tubes 7 are protected from entering of solid particles; moreover, this permits omission of known devices requiring much space and producing strong and undesirable resistance to the passage of combustion gases, which have to be installed in smoke boxes at the bottom of the boiler chimneys in conventional constructions, in order to avoid that sparks leave the chimney.

The considerable decrease of temperature on the long path of the gases after leaving the smoke chamber 4, also contributes to obtain the result that small solid glowing particles become extinguished.

During the period that immediately follows the ignition of the fire in the boiler and the first heating, the combustion gases cool down considerably while passing through the fines 22 of the boiler proper, and reach such a low temperature as not to be able to produce any useful effect when flowing through the nest of tubes 1 contained in the said lower cylindrical shell 6.

Since in the products of combustion there are always vapours contained that condense at cornparatively low temperature, such as water vapour, vapours of sulfur dioxide and heavy hydrocarbons, mixed with solid particles of various kinds, these would deposit and cover the cold walls of the lower cylindrical body 6 and of the preheater tubes l, at a temperature little different from ordinary temperature.

In the embodiment of Fig. 7, these products of combustion are conveyed during the period of starting the boiler to a path different from the path they follow during the regular operation of the boiler. A chimney-like conduit 3! is provided in the smoke chamber 4 and can be closed by means of a cover 38 which can be lifted by operating levers diagrammatically indicated in Fig. 7 at 39. By natural draught or, better, by artificial draught obtained by applying a known blowing device, the products of combustion will escape through the conduit 31 when the cover 3 8 is lifted, which offers less resistance than the longer path through the tubes 1 of the cylindrical body 6.

Closing of the cover 38 to re-establish the normal circuit may be effected when the products of combustion reach the smoke chamber 4 at an appropriate temperature, which will be a consequence of the fact that in the boiler 2 water has reached a high temperature and generates within the boiler a vapour pressure which may be utilized. Around the lower cylindrical preheater body '6, preferably in the zone near to the chimney 2!, a water tight compartment is provided, wherein the steam produced in the boiler is circulated.

The steam coming from the boiler passes through a cylindrical metal jacket 35 surrounding the body is spaced therefrom and condenses at contact with the still cold walls of the cylindrical preheater body 6 yielding a considerable amount of calories. This process will take place very quickly, owing to the very high coefficient of heat transfer of condensing vapours.

The introduction of steam may be effected for example through the aperture 40 and the discharge of condensation water through the aperture 4| located at the lowest point of the jacket 35. It will thus be possible to effect in a very short time a transfer of calories from the boiler to the second compartment and to increase the temperature of the water surrounding the nest flows in countercurrent of tubes i, through which immediately afterwards the products of combustion pass. The heated walls will prevent leaving of any condensed or deposited matter that might produce undesirable clogging deposits.

When more steam under pressure is available, the flowing of the products of combustion into the smoke box 253 and their ejection out of the chimney 2! may be accelerated, bringing about perfect operating conditions for the system.

Above all, with the increase of speed of the products of combustion in the tubes 'l, the above mentioned undesirable substances will hardly deposit any more on the surfaces of said tubes 1.

The vapour jacket 35 may be further utilized when discharge steam coming from the main engine or from the auxiliary engines aboard the locomotive is passed therethrough. In fact, the water to be heated passes through the cylindrical body 6 in countercurrent to the products of combustion and its fiow is very regular, as the preheater tubes define longitudinal conduits and the speed attained is considerable owing to the small cross-sections of the preheater tubes '1. In the peripheral zone defined by the outer preheater tubes and by the preheater body, however, the cross-section of the passage is larger in proportion and the heat transferred to the water would be less if the considerable surface covered by the cylindrical jacket 35 were not utilized as well.

This surface may very conveniently extend as far as the point at which the differences of temnerature of the fluids render a transfer of calories possible. The novel arrangement of the two most important members, the boiler shell I and the lower cylindrical preheater body 6. the right roportion of the surfaces contacted by the flowing products of combustion, and the well calculated sections for passage of the latter, improve the heat transmitting factors and attain maximum efficiency with considerable saving of fuel.

The feeding water enters at a point 28 at the coldest end portion of the preheater body 6, and with respect to the products of combustion around the tubes 1.

On reaching the opposed end of the cylindrical preheater body ii, the water, which will have attained a temperature near to vaporizing, follows the conduit 29 and passes into the boiler shell I, where the addition of heat from the products of combustion will now have no other effect but to transform the water into steam.

As already said, the division into two compartments permits to define well the different purposes thereof, and exact calculation of the dimensions of the members composing them, in such a manner that the surfaces in contact with the gases be increased corresponding to the decrease of the temperature of the latter, and the sections of passage be reduced in accordance with the reduction of specific volume of the products of combustion. In this way, high efficiency is ensured.

In order to more fully show the advantages directly deriving from the invention, an example is given of a boiler with attached preheater bodies as compared with a boiler of the conventional y e- The grates are assumed to be equal in surface in both of said two types and in the nest of fines some are assumed to contain the devices for superheating steam according to the known Schmidt system.

It may be stated at once, that a combustion of pit-coal of such an intensity as to burn 500.11g. per square metre of grate per hour in a convene tional boiler, corresponds to an amount lower than 400 kg. with a boiler of the kind herein described.

The temperature of the products of combustion will not be noticeably different in the two cases, since the less intensive combustion with the boiler according to the invention corresponds to much less passage of excess air, which increases efiiciency.

It may be assumed that owing to convection and radiation, the products of combustion in both cases yield heat proportionately through the walls of the furnace, having about equal surface, the amount of heat being the same so that said products then will pass into the smoke tubes at the same temperature of about 1050 C.

The two nests of tubes will be quite different in that the surface of the boiler according to the invention will be about 40% smaller than the one of the conventional boiler. This reduction, assuming the distance between the tube plates to be equal, results in a reduction to about one half of the number of tubes. In the case of the boiler according to the invention, however, the diameter of the tubes will belarger, as a cross section of passage for the gases is to be obtained which must not be much smaller than in the conventional boiler.

7 There are more tubes of larger diameter 30 containing the steam superheating members 34, provided with regard to the tube 22 as compared with a conventional boiler and it can be said that in general, the surfaces of contact with the gases are approximately equal to each other with both types of tubes, large and small.

If surfaces and cross sections are correctly designed, the products of combustion will reach the calories still in the products of combustion are transmitted to the water, which is heated up to a temperature only little lower than that required for subsequent vaporization in the boiler. If the temperature of the gases in the smoke chamber of the body i is about 390 C., they will arrive at the chimney 2! ofthe cylindrical body E at a temperature of 150 C. about 240 C. cooler.

Of course, to up for the smaller capacity of transmission of heat caused by the smaller thermal drop between gases and water therein, the cross section of the passage is notably reduced to such an extent as to maintain the speed of the gases high (which is an essential condition for a high coefficient of transmission by convec tion) and in proportion with the reduced average specific volume corresponding to a lower temperature.

All this cannot occur with a boiler of the conventional kind, even if longitudinal or transversal separating walls would be installed therewith in order to compel the fluids to flow along predetermined paths. At any rate, it would not be possiblewith a conventional boiler, for instance, to reduce the section of passage for gas in accord- .ance with their contracted volume due to diminished temperature, and to increase the heat trans mission coefiicient.

An unquestionable advantage of the boiler herein described lies in the location and dimensions of its various members. The cylindrical. preheater bodies occupy a space below the boiler which often, is. not utilized or, in any case, is poorly utilized.

Still as compared with a corresponding conventional boiler, having the same distance between the tube plates, the cylindrical body of the boiler according to the present invention will have a diameter smaller by atleast 15%, owing to the smaller number of dues composing the nest, half the number of flues used in a conventional boiler being suincient. The two cylindrical preheater bodies under the boiler each have a diameter equal to about half the diameter of the boiler and may therefore be conveniently arranged under it.

With such an arrangement, it is self-evident that the firebox can be made higher, which is. a great advantage for the improvement of combustion.

This arrangement is satisfactory also with respect to the position of the centre of mass, in vertical and horizontal directions, so that the conventional arrangement of the axes, of the frame and of the drive mechanisms can be perfectly maintained in locomotives.

As a consequence. it becomes possible to replace a conventional boiler with a boiler of the type herein described in conventional locomotives without any special modifications.

Having now particularly described and ascertained the nature or my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. A steam boiler, comprising in combination, a substantially horizontal elongated boiler shell; a fire box at the front end of said boiler shell; a smoke chamber arranged at the rear end of said boiler shell and being of greater height than said boiler shell and projecting downwardly therebelow; a plurality of cylindrical flues arranged in said boiler shell and communicating with said fire box and said smoke chamber; at least one cylindrical preheater body located under said boiler shell and sloped with regard thereto and projecting at one end with its higher portion into said smoke chamber; a smoke box at the other end of said cylindrical heater body; at least one chimney on said smoke box; a plurality of preheater tubes located in said cylindrical preheater body parallel to its axis and communicating with said smoke box and with said smoke chamber, whereby a continuous path for the flow of combustion gasesis formed extending from said fire box through said flues into said smoke chamber and then in opposite direction through said preheater tubes intosaid smoke box and chimney; a water inlet arranged on said inclined preheater body in the lowest portion thereof outside of said smoke chamber; a Water outlet arranged in said inclined preheater body in the highest portion thereof inside said smoke chamber; a. water pipe passing through said smoke chamber and connecting said water outlet in said preheater body with the interior of said boiler shell whereby a path for the flow of water is formed extendin through said preheater body in countercurrent relation with the flow of the combustion gases in said preheater tubes, through said water pipe into the interior of said boiler shell; substantially horizontal plate means for retaining ashes dividing said smoke chamber into an upper part and a lower part and arranged in said smoke chamber below said fiues and, above said higher portion of said preheater body projecting into said smoke chamber; and door means arranged in said smoke chamber in its end wall opposite said boiler shell and said preheater body and being of such height and width as to permit access to the interior of said boiler shell and said preheater body and formed with a vertical wall portion cooperating with said plate means in retainin ashes and with a conduit connecting said upper and said lower part of said smoke cham her.

2. A steam boiler, comprising, in combination, a substantially horizontal elongated boiler shell; a plurality of fiues in said boiler shell; a fire box at one end of said boiler shell; a smoke chamber located at the other end of said boiler shell communicating with said flues, said smoke chamber being of greater height than said boiler shell and projecting downwardly therefrom, said smoke chamber having an opening located oppositely said boiler shell; a plurality of fines arranged in said boiler shell communicating with said fire box and with the upper portion of said smoke chamher; at least one elongated tubular heater body partly located in said smoke chamber projecting therefrom under said boiler shell in substantially the same direction as the same; a set of parallel preheater tubes located in said tubular heater body and communicating with said smoke cham ber whereby a continuous path for the flow of combustion gases is formed extending from said fire box through said fiues into said smoke chamber and then in opposite directions through said preheater tubes; supporting end plates attached to said set of parallel preheater tubes and holding the same together so as to form a removable unit; means detach-ably securing said supporting end plates to the ends of said tubular heater body; and door means arranged in said smoke chamber oppositely said other end of said boiler shell and said one end of said heater body for closing said opening of said smoke chamber, said opening being arranged oppositely to said other end of said boiler shell and to said one end of said tubular heater body and having such height and width as to permit insertion and removal of said removable unit into and out of said tubular heater body therethrough, and also to permit access to the interior of said boiler shell.

3. A steam boiler, comprising, in combination, a substantially horizontal elongated boiler shell; a fire box at one end of said boiler shell; a smoke chamber located at the other end of said boiler shell communicating with said fiues, said smoke chamber being of greater height than said boiler shell and projecting downwardly therefrom, said smoke chamber having an opening located oppositely said boiler shell; a plurality of flues arranged in said boiler shell communicating with said fire box and with the upper portion of said smoke chamber; at least one elongated tubular heater body partly located in said smoke chamber projectingtherefrom under said boiler shell in substantially the same direction as said elongated boiler shell; a set of parallel preheater tubes located in said tubular heater body and communicating with said smoke chamber whereby a continuous path for the flow of combustion gases is formed extending from said fire box through said fiues into said smoke chamber and then in opposite directions through said preheater tubes; supporting end plates attached to said set of parallel preheater tubes and holding the same together so as to form a removable unit; means detachably securing said supporting end plates to the ends of said tubular heater body; substantially horizontally extending partitioning means for retaining ashes located in said smoke chamber below said fiues and above said heater body and dividing said smoke chamber into an upper portion communicating with said flues and a lower portion communicating with said tubes; door means arranged in said smoke chamber oppositely said other end of said boiler shell and said one end of said heater body for closing said opening of said smoke chamber, said opening being arranged oppositely to said other end of said boiler shell and to said one end of said tubular-heater body and having such height and width as to permit insertion and removal of said removable unit into and out of said tubular heater body therethrough, and also to permit access to the interior of said boiler shell; and conduit means at least partly bounded by said door means and connecting said upper portion and said lower portion of said smoke chamber.

4, A boiler, comprising, in combination, a fire box; a smoke chamber located spaced from said fire box; partitioning means located in said smoke chamber and dividing the same into an upper portion and a lower portion; a boiler shell having a water outlet; fiue pipe means located in said boiler shell communicating at one end thereof with said fire box, and at the other end thereof with said upper portion of said smoke chamber; at least one tubular preheater body partly located in said lower portion of said smoke chamber, and partly projectin therefrom towards said fire box; a smoke box having a smoke outlet and located adjacent to said fire box at the projecting end of said tubular preheater body; a set of preheater tubes located in said tubular preheater body and communicating at one end thereof with said lower portion of said smoke chamber and with the other end thereof with said smoke box; a door arranged in said smoke chamber extending over said upper portion and said lower portion and oppositely said flue pipes and said preheater tubes, said door forming at least part of a conduit connecting said upper portion of said smoke chamber with said lower portion or" said smoke chamber so that combustion gases may pass through said flue pipes, said upper portion of said smoke chamber, said conduit, and said preheater tubes into said smoke box; water inlet means located on said tubular preheater body at said projecting end thereof; water outlet means located on said tubular preheater body in said lower portion of said smoke chamber and communicating with said boiler shell so that water passes through said tubular preheater body in counter-current with the combustion gases passingthrough said preheater tubes and is simultaneously heated by the combustion gases entering said lower portion of said smoke chamber through said conduit.

5. A boiler, comprising, in combination, a fire box; a smoke chamber located spaced from said fire box; horizontal partitioning means located in said smoke chamber and dividing the same into an upper portion and a lower portion; a boiler shell having a water outlet; flue pipe means located in said boiler shell communicating at one end thereof with said fire box, and at the other end thereof with said upper portion of said smoke chamber; at least one tubular preheater body partly located in said lower portion of said smoke chamber, and partly projecting therefrom towards said fire box; a smoke box having a smoke outlet and located adjacent to said fire box at tubular preheater body and communicating at one end thereof with said lower" portion of said smoke chamber and with the other end thereof with said smoke box; a substantially vertical door arranged in said smoke chamber extendingover all said upper portion and all said lower portion and oppositely said flue pipes and said preheater tubes, said door being formed with a conduit connecting said upper portion of said smoke chamber with said lower portion of said smoke chamber so that combustion gases may pass through said flue pipes, said upper portion of said smoke chamber, said conduit, and said preheater tubes into said smoke box; water inlet means located on said tubular preheater body at said pro- .jecting end thereof; water outlet means located on said tubular preheater body in said lower portion of said smoke chamber and communicating with said boiler shell so that Water passes through said tubular preheater body in counter- 19 current with the combustion gases passing through said preheater tubes and is simultaneously heated by the combustion gases entering said lower portion of said smoke chamber through said conduit.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 462,613 Barlet Nov. 3, 1891 629,096 Stevens July 18, 1899 808,178 Trevithick Dec. 26, 1905 834,131 Hibbard Oct. 23, 1906 854,016 Ballewski et al May 21, 1907 913,249 Aldrich Feb. 23, 1909' 1,132,778 Kerner Mar. 23, 1915 1,838,266 Kreager Dec. 29, 1931 1,982,793 Davis Dec. 4, 1934 2,200,492 Crosti May 14, 1940 FOREIGN PATENTS Number Country Date 174,498 Germany Sept. 11, 1906 269,997 Great Britain May 2, 1927 274,123 Great Britain July 19, 1928 

